upload-pack.con commit checkout: notice when the switched branch is behind or forked (79a1e6b)
   1#include "cache.h"
   2#include "refs.h"
   3#include "pkt-line.h"
   4#include "sideband.h"
   5#include "tag.h"
   6#include "object.h"
   7#include "commit.h"
   8#include "exec_cmd.h"
   9#include "diff.h"
  10#include "revision.h"
  11#include "list-objects.h"
  12#include "run-command.h"
  13
  14static const char upload_pack_usage[] = "git-upload-pack [--strict] [--timeout=nn] <dir>";
  15
  16/* bits #0..7 in revision.h, #8..10 in commit.c */
  17#define THEY_HAVE       (1u << 11)
  18#define OUR_REF         (1u << 12)
  19#define WANTED          (1u << 13)
  20#define COMMON_KNOWN    (1u << 14)
  21#define REACHABLE       (1u << 15)
  22
  23#define SHALLOW         (1u << 16)
  24#define NOT_SHALLOW     (1u << 17)
  25#define CLIENT_SHALLOW  (1u << 18)
  26
  27static unsigned long oldest_have;
  28
  29static int multi_ack, nr_our_refs;
  30static int use_thin_pack, use_ofs_delta, no_progress;
  31static struct object_array have_obj;
  32static struct object_array want_obj;
  33static unsigned int timeout;
  34/* 0 for no sideband,
  35 * otherwise maximum packet size (up to 65520 bytes).
  36 */
  37static int use_sideband;
  38
  39static void reset_timeout(void)
  40{
  41        alarm(timeout);
  42}
  43
  44static int strip(char *line, int len)
  45{
  46        if (len && line[len-1] == '\n')
  47                line[--len] = 0;
  48        return len;
  49}
  50
  51static ssize_t send_client_data(int fd, const char *data, ssize_t sz)
  52{
  53        if (use_sideband)
  54                return send_sideband(1, fd, data, sz, use_sideband);
  55        if (fd == 3)
  56                /* emergency quit */
  57                fd = 2;
  58        if (fd == 2) {
  59                /* XXX: are we happy to lose stuff here? */
  60                xwrite(fd, data, sz);
  61                return sz;
  62        }
  63        return safe_write(fd, data, sz);
  64}
  65
  66static FILE *pack_pipe = NULL;
  67static void show_commit(struct commit *commit)
  68{
  69        if (commit->object.flags & BOUNDARY)
  70                fputc('-', pack_pipe);
  71        if (fputs(sha1_to_hex(commit->object.sha1), pack_pipe) < 0)
  72                die("broken output pipe");
  73        fputc('\n', pack_pipe);
  74        fflush(pack_pipe);
  75        free(commit->buffer);
  76        commit->buffer = NULL;
  77}
  78
  79static void show_object(struct object_array_entry *p)
  80{
  81        /* An object with name "foo\n0000000..." can be used to
  82         * confuse downstream git-pack-objects very badly.
  83         */
  84        const char *ep = strchr(p->name, '\n');
  85        if (ep) {
  86                fprintf(pack_pipe, "%s %.*s\n", sha1_to_hex(p->item->sha1),
  87                       (int) (ep - p->name),
  88                       p->name);
  89        }
  90        else
  91                fprintf(pack_pipe, "%s %s\n",
  92                                sha1_to_hex(p->item->sha1), p->name);
  93}
  94
  95static void show_edge(struct commit *commit)
  96{
  97        fprintf(pack_pipe, "-%s\n", sha1_to_hex(commit->object.sha1));
  98}
  99
 100static int do_rev_list(int fd, void *create_full_pack)
 101{
 102        int i;
 103        struct rev_info revs;
 104
 105        pack_pipe = fdopen(fd, "w");
 106        if (create_full_pack)
 107                use_thin_pack = 0; /* no point doing it */
 108        init_revisions(&revs, NULL);
 109        revs.tag_objects = 1;
 110        revs.tree_objects = 1;
 111        revs.blob_objects = 1;
 112        if (use_thin_pack)
 113                revs.edge_hint = 1;
 114
 115        if (create_full_pack) {
 116                const char *args[] = {"rev-list", "--all", NULL};
 117                setup_revisions(2, args, &revs, NULL);
 118        } else {
 119                for (i = 0; i < want_obj.nr; i++) {
 120                        struct object *o = want_obj.objects[i].item;
 121                        /* why??? */
 122                        o->flags &= ~UNINTERESTING;
 123                        add_pending_object(&revs, o, NULL);
 124                }
 125                for (i = 0; i < have_obj.nr; i++) {
 126                        struct object *o = have_obj.objects[i].item;
 127                        o->flags |= UNINTERESTING;
 128                        add_pending_object(&revs, o, NULL);
 129                }
 130                setup_revisions(0, NULL, &revs, NULL);
 131        }
 132        prepare_revision_walk(&revs);
 133        mark_edges_uninteresting(revs.commits, &revs, show_edge);
 134        traverse_commit_list(&revs, show_commit, show_object);
 135        return 0;
 136}
 137
 138static void create_pack_file(void)
 139{
 140        struct async rev_list;
 141        struct child_process pack_objects;
 142        int create_full_pack = (nr_our_refs == want_obj.nr && !have_obj.nr);
 143        char data[8193], progress[128];
 144        char abort_msg[] = "aborting due to possible repository "
 145                "corruption on the remote side.";
 146        int buffered = -1;
 147        ssize_t sz;
 148        const char *argv[10];
 149        int arg = 0;
 150
 151        rev_list.proc = do_rev_list;
 152        /* .data is just a boolean: any non-NULL value will do */
 153        rev_list.data = create_full_pack ? &rev_list : NULL;
 154        if (start_async(&rev_list))
 155                die("git-upload-pack: unable to fork git-rev-list");
 156
 157        argv[arg++] = "pack-objects";
 158        argv[arg++] = "--stdout";
 159        if (!no_progress)
 160                argv[arg++] = "--progress";
 161        if (use_ofs_delta)
 162                argv[arg++] = "--delta-base-offset";
 163        argv[arg++] = NULL;
 164
 165        memset(&pack_objects, 0, sizeof(pack_objects));
 166        pack_objects.in = rev_list.out; /* start_command closes it */
 167        pack_objects.out = -1;
 168        pack_objects.err = -1;
 169        pack_objects.git_cmd = 1;
 170        pack_objects.argv = argv;
 171
 172        if (start_command(&pack_objects))
 173                die("git-upload-pack: unable to fork git-pack-objects");
 174
 175        /* We read from pack_objects.err to capture stderr output for
 176         * progress bar, and pack_objects.out to capture the pack data.
 177         */
 178
 179        while (1) {
 180                struct pollfd pfd[2];
 181                int pe, pu, pollsize;
 182
 183                reset_timeout();
 184
 185                pollsize = 0;
 186                pe = pu = -1;
 187
 188                if (0 <= pack_objects.out) {
 189                        pfd[pollsize].fd = pack_objects.out;
 190                        pfd[pollsize].events = POLLIN;
 191                        pu = pollsize;
 192                        pollsize++;
 193                }
 194                if (0 <= pack_objects.err) {
 195                        pfd[pollsize].fd = pack_objects.err;
 196                        pfd[pollsize].events = POLLIN;
 197                        pe = pollsize;
 198                        pollsize++;
 199                }
 200
 201                if (!pollsize)
 202                        break;
 203
 204                if (poll(pfd, pollsize, -1) < 0) {
 205                        if (errno != EINTR) {
 206                                error("poll failed, resuming: %s",
 207                                      strerror(errno));
 208                                sleep(1);
 209                        }
 210                        continue;
 211                }
 212                if (0 <= pu && (pfd[pu].revents & (POLLIN|POLLHUP))) {
 213                        /* Data ready; we keep the last byte to ourselves
 214                         * in case we detect broken rev-list, so that we
 215                         * can leave the stream corrupted.  This is
 216                         * unfortunate -- unpack-objects would happily
 217                         * accept a valid packdata with trailing garbage,
 218                         * so appending garbage after we pass all the
 219                         * pack data is not good enough to signal
 220                         * breakage to downstream.
 221                         */
 222                        char *cp = data;
 223                        ssize_t outsz = 0;
 224                        if (0 <= buffered) {
 225                                *cp++ = buffered;
 226                                outsz++;
 227                        }
 228                        sz = xread(pack_objects.out, cp,
 229                                  sizeof(data) - outsz);
 230                        if (0 < sz)
 231                                        ;
 232                        else if (sz == 0) {
 233                                close(pack_objects.out);
 234                                pack_objects.out = -1;
 235                        }
 236                        else
 237                                goto fail;
 238                        sz += outsz;
 239                        if (1 < sz) {
 240                                buffered = data[sz-1] & 0xFF;
 241                                sz--;
 242                        }
 243                        else
 244                                buffered = -1;
 245                        sz = send_client_data(1, data, sz);
 246                        if (sz < 0)
 247                                goto fail;
 248                }
 249                if (0 <= pe && (pfd[pe].revents & (POLLIN|POLLHUP))) {
 250                        /* Status ready; we ship that in the side-band
 251                         * or dump to the standard error.
 252                         */
 253                        sz = xread(pack_objects.err, progress,
 254                                  sizeof(progress));
 255                        if (0 < sz)
 256                                send_client_data(2, progress, sz);
 257                        else if (sz == 0) {
 258                                close(pack_objects.err);
 259                                pack_objects.err = -1;
 260                        }
 261                        else
 262                                goto fail;
 263                }
 264        }
 265
 266        if (finish_command(&pack_objects)) {
 267                error("git-upload-pack: git-pack-objects died with error.");
 268                goto fail;
 269        }
 270        if (finish_async(&rev_list))
 271                goto fail;      /* error was already reported */
 272
 273        /* flush the data */
 274        if (0 <= buffered) {
 275                data[0] = buffered;
 276                sz = send_client_data(1, data, 1);
 277                if (sz < 0)
 278                        goto fail;
 279                fprintf(stderr, "flushed.\n");
 280        }
 281        if (use_sideband)
 282                packet_flush(1);
 283        return;
 284
 285 fail:
 286        send_client_data(3, abort_msg, sizeof(abort_msg));
 287        die("git-upload-pack: %s", abort_msg);
 288}
 289
 290static int got_sha1(char *hex, unsigned char *sha1)
 291{
 292        struct object *o;
 293        int we_knew_they_have = 0;
 294
 295        if (get_sha1_hex(hex, sha1))
 296                die("git-upload-pack: expected SHA1 object, got '%s'", hex);
 297        if (!has_sha1_file(sha1))
 298                return -1;
 299
 300        o = lookup_object(sha1);
 301        if (!(o && o->parsed))
 302                o = parse_object(sha1);
 303        if (!o)
 304                die("oops (%s)", sha1_to_hex(sha1));
 305        if (o->type == OBJ_COMMIT) {
 306                struct commit_list *parents;
 307                struct commit *commit = (struct commit *)o;
 308                if (o->flags & THEY_HAVE)
 309                        we_knew_they_have = 1;
 310                else
 311                        o->flags |= THEY_HAVE;
 312                if (!oldest_have || (commit->date < oldest_have))
 313                        oldest_have = commit->date;
 314                for (parents = commit->parents;
 315                     parents;
 316                     parents = parents->next)
 317                        parents->item->object.flags |= THEY_HAVE;
 318        }
 319        if (!we_knew_they_have) {
 320                add_object_array(o, NULL, &have_obj);
 321                return 1;
 322        }
 323        return 0;
 324}
 325
 326static int reachable(struct commit *want)
 327{
 328        struct commit_list *work = NULL;
 329
 330        insert_by_date(want, &work);
 331        while (work) {
 332                struct commit_list *list = work->next;
 333                struct commit *commit = work->item;
 334                free(work);
 335                work = list;
 336
 337                if (commit->object.flags & THEY_HAVE) {
 338                        want->object.flags |= COMMON_KNOWN;
 339                        break;
 340                }
 341                if (!commit->object.parsed)
 342                        parse_object(commit->object.sha1);
 343                if (commit->object.flags & REACHABLE)
 344                        continue;
 345                commit->object.flags |= REACHABLE;
 346                if (commit->date < oldest_have)
 347                        continue;
 348                for (list = commit->parents; list; list = list->next) {
 349                        struct commit *parent = list->item;
 350                        if (!(parent->object.flags & REACHABLE))
 351                                insert_by_date(parent, &work);
 352                }
 353        }
 354        want->object.flags |= REACHABLE;
 355        clear_commit_marks(want, REACHABLE);
 356        free_commit_list(work);
 357        return (want->object.flags & COMMON_KNOWN);
 358}
 359
 360static int ok_to_give_up(void)
 361{
 362        int i;
 363
 364        if (!have_obj.nr)
 365                return 0;
 366
 367        for (i = 0; i < want_obj.nr; i++) {
 368                struct object *want = want_obj.objects[i].item;
 369
 370                if (want->flags & COMMON_KNOWN)
 371                        continue;
 372                want = deref_tag(want, "a want line", 0);
 373                if (!want || want->type != OBJ_COMMIT) {
 374                        /* no way to tell if this is reachable by
 375                         * looking at the ancestry chain alone, so
 376                         * leave a note to ourselves not to worry about
 377                         * this object anymore.
 378                         */
 379                        want_obj.objects[i].item->flags |= COMMON_KNOWN;
 380                        continue;
 381                }
 382                if (!reachable((struct commit *)want))
 383                        return 0;
 384        }
 385        return 1;
 386}
 387
 388static int get_common_commits(void)
 389{
 390        static char line[1000];
 391        unsigned char sha1[20];
 392        char hex[41], last_hex[41];
 393        int len;
 394
 395        track_object_refs = 0;
 396        save_commit_buffer = 0;
 397
 398        for(;;) {
 399                len = packet_read_line(0, line, sizeof(line));
 400                reset_timeout();
 401
 402                if (!len) {
 403                        if (have_obj.nr == 0 || multi_ack)
 404                                packet_write(1, "NAK\n");
 405                        continue;
 406                }
 407                len = strip(line, len);
 408                if (!prefixcmp(line, "have ")) {
 409                        switch (got_sha1(line+5, sha1)) {
 410                        case -1: /* they have what we do not */
 411                                if (multi_ack && ok_to_give_up())
 412                                        packet_write(1, "ACK %s continue\n",
 413                                                     sha1_to_hex(sha1));
 414                                break;
 415                        default:
 416                                memcpy(hex, sha1_to_hex(sha1), 41);
 417                                if (multi_ack) {
 418                                        const char *msg = "ACK %s continue\n";
 419                                        packet_write(1, msg, hex);
 420                                        memcpy(last_hex, hex, 41);
 421                                }
 422                                else if (have_obj.nr == 1)
 423                                        packet_write(1, "ACK %s\n", hex);
 424                                break;
 425                        }
 426                        continue;
 427                }
 428                if (!strcmp(line, "done")) {
 429                        if (have_obj.nr > 0) {
 430                                if (multi_ack)
 431                                        packet_write(1, "ACK %s\n", last_hex);
 432                                return 0;
 433                        }
 434                        packet_write(1, "NAK\n");
 435                        return -1;
 436                }
 437                die("git-upload-pack: expected SHA1 list, got '%s'", line);
 438        }
 439}
 440
 441static void receive_needs(void)
 442{
 443        struct object_array shallows = {0, 0, NULL};
 444        static char line[1000];
 445        int len, depth = 0;
 446
 447        for (;;) {
 448                struct object *o;
 449                unsigned char sha1_buf[20];
 450                len = packet_read_line(0, line, sizeof(line));
 451                reset_timeout();
 452                if (!len)
 453                        break;
 454
 455                if (!prefixcmp(line, "shallow ")) {
 456                        unsigned char sha1[20];
 457                        struct object *object;
 458                        use_thin_pack = 0;
 459                        if (get_sha1(line + 8, sha1))
 460                                die("invalid shallow line: %s", line);
 461                        object = parse_object(sha1);
 462                        if (!object)
 463                                die("did not find object for %s", line);
 464                        object->flags |= CLIENT_SHALLOW;
 465                        add_object_array(object, NULL, &shallows);
 466                        continue;
 467                }
 468                if (!prefixcmp(line, "deepen ")) {
 469                        char *end;
 470                        use_thin_pack = 0;
 471                        depth = strtol(line + 7, &end, 0);
 472                        if (end == line + 7 || depth <= 0)
 473                                die("Invalid deepen: %s", line);
 474                        continue;
 475                }
 476                if (prefixcmp(line, "want ") ||
 477                    get_sha1_hex(line+5, sha1_buf))
 478                        die("git-upload-pack: protocol error, "
 479                            "expected to get sha, not '%s'", line);
 480                if (strstr(line+45, "multi_ack"))
 481                        multi_ack = 1;
 482                if (strstr(line+45, "thin-pack"))
 483                        use_thin_pack = 1;
 484                if (strstr(line+45, "ofs-delta"))
 485                        use_ofs_delta = 1;
 486                if (strstr(line+45, "side-band-64k"))
 487                        use_sideband = LARGE_PACKET_MAX;
 488                else if (strstr(line+45, "side-band"))
 489                        use_sideband = DEFAULT_PACKET_MAX;
 490                if (strstr(line+45, "no-progress"))
 491                        no_progress = 1;
 492
 493                /* We have sent all our refs already, and the other end
 494                 * should have chosen out of them; otherwise they are
 495                 * asking for nonsense.
 496                 *
 497                 * Hmph.  We may later want to allow "want" line that
 498                 * asks for something like "master~10" (symbolic)...
 499                 * would it make sense?  I don't know.
 500                 */
 501                o = lookup_object(sha1_buf);
 502                if (!o || !(o->flags & OUR_REF))
 503                        die("git-upload-pack: not our ref %s", line+5);
 504                if (!(o->flags & WANTED)) {
 505                        o->flags |= WANTED;
 506                        add_object_array(o, NULL, &want_obj);
 507                }
 508        }
 509        if (depth == 0 && shallows.nr == 0)
 510                return;
 511        if (depth > 0) {
 512                struct commit_list *result, *backup;
 513                int i;
 514                backup = result = get_shallow_commits(&want_obj, depth,
 515                        SHALLOW, NOT_SHALLOW);
 516                while (result) {
 517                        struct object *object = &result->item->object;
 518                        if (!(object->flags & (CLIENT_SHALLOW|NOT_SHALLOW))) {
 519                                packet_write(1, "shallow %s",
 520                                                sha1_to_hex(object->sha1));
 521                                register_shallow(object->sha1);
 522                        }
 523                        result = result->next;
 524                }
 525                free_commit_list(backup);
 526                for (i = 0; i < shallows.nr; i++) {
 527                        struct object *object = shallows.objects[i].item;
 528                        if (object->flags & NOT_SHALLOW) {
 529                                struct commit_list *parents;
 530                                packet_write(1, "unshallow %s",
 531                                        sha1_to_hex(object->sha1));
 532                                object->flags &= ~CLIENT_SHALLOW;
 533                                /* make sure the real parents are parsed */
 534                                unregister_shallow(object->sha1);
 535                                object->parsed = 0;
 536                                parse_commit((struct commit *)object);
 537                                parents = ((struct commit *)object)->parents;
 538                                while (parents) {
 539                                        add_object_array(&parents->item->object,
 540                                                        NULL, &want_obj);
 541                                        parents = parents->next;
 542                                }
 543                        }
 544                        /* make sure commit traversal conforms to client */
 545                        register_shallow(object->sha1);
 546                }
 547                packet_flush(1);
 548        } else
 549                if (shallows.nr > 0) {
 550                        int i;
 551                        for (i = 0; i < shallows.nr; i++)
 552                                register_shallow(shallows.objects[i].item->sha1);
 553                }
 554        free(shallows.objects);
 555}
 556
 557static int send_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
 558{
 559        static const char *capabilities = "multi_ack thin-pack side-band"
 560                " side-band-64k ofs-delta shallow no-progress";
 561        struct object *o = parse_object(sha1);
 562
 563        if (!o)
 564                die("git-upload-pack: cannot find object %s:", sha1_to_hex(sha1));
 565
 566        if (capabilities)
 567                packet_write(1, "%s %s%c%s\n", sha1_to_hex(sha1), refname,
 568                        0, capabilities);
 569        else
 570                packet_write(1, "%s %s\n", sha1_to_hex(sha1), refname);
 571        capabilities = NULL;
 572        if (!(o->flags & OUR_REF)) {
 573                o->flags |= OUR_REF;
 574                nr_our_refs++;
 575        }
 576        if (o->type == OBJ_TAG) {
 577                o = deref_tag(o, refname, 0);
 578                packet_write(1, "%s %s^{}\n", sha1_to_hex(o->sha1), refname);
 579        }
 580        return 0;
 581}
 582
 583static void upload_pack(void)
 584{
 585        reset_timeout();
 586        head_ref(send_ref, NULL);
 587        for_each_ref(send_ref, NULL);
 588        packet_flush(1);
 589        receive_needs();
 590        if (want_obj.nr) {
 591                get_common_commits();
 592                create_pack_file();
 593        }
 594}
 595
 596int main(int argc, char **argv)
 597{
 598        char *dir;
 599        int i;
 600        int strict = 0;
 601
 602        for (i = 1; i < argc; i++) {
 603                char *arg = argv[i];
 604
 605                if (arg[0] != '-')
 606                        break;
 607                if (!strcmp(arg, "--strict")) {
 608                        strict = 1;
 609                        continue;
 610                }
 611                if (!prefixcmp(arg, "--timeout=")) {
 612                        timeout = atoi(arg+10);
 613                        continue;
 614                }
 615                if (!strcmp(arg, "--")) {
 616                        i++;
 617                        break;
 618                }
 619        }
 620
 621        if (i != argc-1)
 622                usage(upload_pack_usage);
 623        dir = argv[i];
 624
 625        if (!enter_repo(dir, strict))
 626                die("'%s': unable to chdir or not a git archive", dir);
 627        if (is_repository_shallow())
 628                die("attempt to fetch/clone from a shallow repository");
 629        upload_pack();
 630        return 0;
 631}